diff --git a/mozilla/layout/html/document/src/forms.css b/mozilla/layout/html/document/src/forms.css
index 42b99a1870a..42c8c900222 100644
--- a/mozilla/layout/html/document/src/forms.css
+++ b/mozilla/layout/html/document/src/forms.css
@@ -186,7 +186,6 @@ optgroup:before {
 *|*:-moz-dropdown-list {
   background-color: inherit;
   border: 1px outset black; 
-  border-top-style: none;
   z-index: 2147483647;
   -moz-user-select: none;
 } 
diff --git a/mozilla/layout/style/forms.css b/mozilla/layout/style/forms.css
index 42b99a1870a..42c8c900222 100644
--- a/mozilla/layout/style/forms.css
+++ b/mozilla/layout/style/forms.css
@@ -186,7 +186,6 @@ optgroup:before {
 *|*:-moz-dropdown-list {
   background-color: inherit;
   border: 1px outset black; 
-  border-top-style: none;
   z-index: 2147483647;
   -moz-user-select: none;
 }